Aluminum hydroxide is produced on an industrial scale by well-established methods such as the Bayer process. The precipitation process operators optimize their methods so as to produce the greatest possible yield from the aluminate process liquors while trying to achieve a particular crystal size distribution of aluminum hydroxide product. It is desirable in most instances to obtain the product of relatively large crystal size and to correspondingly limit the amount of very fine crystals since this is beneficial in subsequent processing steps required to produce aluminum metal. Production is often limited by processing conditions under which the crystallization and precipitation is conducted. These processing conditions vary from one plant to the next and include, but are not limited to, temperature profiles, seed charge, seed crystal surface area, purge of carbon dioxide or flue gases, liquor loading, liquor purity, and the like.
Extensive efforts have been invested into finding chemical additives and methods limiting the factors negatively affecting particle size in order to achieve the optimal economic recovery of aluminum hydroxide product.
Despite the continuous and ongoing development worldwide, the industry demands for more economical resolution of the above-described process needs remain. A method of such resolution suitable for obtaining aluminum hydroxide crystals with increased particle size is provided by the present invention.